SANTA CLARA -- Yes, the expectation was clear for Eric Reid the moment the club traded up 13 spots to take him with the 18th overall pick in the draft. But, now, those expectations are worthless. Training camp has started and jobs are won or lost on the field.

"If you look back to when we drafted Aldon Smith, who was the seventh pick in the draft, he didn't start as a nickel rusher until after the last preseason game, which is when he actually went out and won that job," 49ers defensive coordinator Vic Fangio said on Friday.

"So nothing was given to Aldon that year, and nothing is going to be given to Eric this year. He's got to go out and earn it."

Veteran Parys Haralson maintained the starting job in the 49ers' base defense at outside linebacker in 2011. Smith entered in pass-rush situations and recorded a team-high 14 sacks as a rookie.

The 49ers are certainly not expecting the equivalent of that kind of contributions from Reid in his first season, but he will certainly have an opportunity for a significant role.

After the 49ers lost All-Pro safety Dashon Goldson in free agency to the Tampa Bay Buccaneers, the 49ers signed veteran Craig Dahl, who started all 16 games a year ago with the St. Louis Rams.

C.J. Spillman, the 49ers' third safety a year ago, and second-year player Trenton Robinson will also get a chance to prove themselves in the competition.

"Right now, it's a battle, as I see it, between four guys because Trenton had a good offseason and put him in the mix there, too, between Eric, Dahl and C.J.," Fangio said.

"It'll sort itself out. One good thing about training camp is we get a lot of reps. Everybody will get a lot of work and it'll sort itself out."